¿ªÔÆÌåÓý

  1. Losmandy_users
  2. Topics

Losmandy G11 bearing question

 

Folks,
?
I'm doing a deep dive into my G11 and replaced all the bearings. One thing I noticed is while replacing the inner needle bearings is that one end of the RA and Dec axis housings have enough room to fit two needle bearings. See photos. Do you think it would help in any way to add another bearing in this space?
?
-Frank
?
 

¿ªÔÆÌåÓý

Yes,

??? Years ago I added a third bearing to the axis and it markedly stabilized the tracking.? If you search the archives you will find a lively discussion about this and how to do the addition.

Laurel

On 4/24/25 4:31 PM, fetoma via groups.io wrote:
You don't often get email from fetoma@....

? [EXTERNAL]

Folks,
?
I'm doing a deep dive into my G11 and replaced all the bearings. One thing I noticed is while replacing the inner needle bearings is that one end of the RA and Dec axis housings have enough room to fit two needle bearings. See photos. Do you think it would help in any way to add another bearing in this space?
?
-Frank
?
 

On Thu, Apr 24, 2025 at 06:31 PM, fetoma wrote:
I'm doing a deep dive into my G11 and replaced all the bearings. One thing I noticed is while replacing the inner needle bearings is that one end of the RA and Dec axis housings have enough room to fit two needle bearings. See photos. Do you think it would help in any way to add another bearing in this space?
Hi Frank,
?
Just as Laurel, I added a third bearing to a G11 more than 20 years ago, when I was planning to put a 10" SCT on it side-by-side with a small refractor. The thinking was to stabilize the axis, fix it so there's little chance of a wobble. It took some effort to install the third bearing -- I didn't have any specialized equipment to do so.
?
What was worse was that it became nearly impossible to push the axis through the three bearings. With three bearings that are properly sized, you'll need to make sure that all three are aligned very precisely, that none are even slightly tilted relative to the others. Any slight tilt of the new bearing will surely help secure the axis better, but will also make it nearly impossible to get the axis threaded through all three of them! :( It took me nearly a day to rectify a slight tilt I introduced with the new bearing. The one I installed fit very snuggly into the axis tube, so making adjustments to its position was not easy.
?
I can't say for sure that it improved anything with the mount, but after all the pain and suffering, the G11 performed well for years, and I still have it and use it on occasion when I need a portable set up :)
?
Regards,
?
? ?-Paul
 

?
?
Hi Paul,
?
Binding due to misalignment is one of the problems I found as a potential way to screw up my perfectly good G11 mount as I contemplated this modification.? To get that perfect non-binding installation the additional bearing would need to be supported on a shaft that is in alignment with the other two bearings as the 3rd is pressed into place.??
?
So when I looked at the distance between the bearings and the very short length the axle? is unsupported at the end of the body I figured it should make no difference.? My guess was it would not improve performance even if the 3rd bearing was installed perfectly.? But if not installed perfectly or the axle was not perfectly straight the slight misalignment could be the source of a slight, regular binding as the axle rotated.? So I passed on that modification.??
?
--

Chip Louie Chief Daydreamer Imagination Hardware?

Astrospheric Forecast - South Pasadena, CA?
?
?
?
 

On Fri, Apr 25, 2025 at 10:09 AM, Chip Louie wrote:
Binding due to misalignment is one of the problems I found as a potential way to screw up my perfectly good G11 mount as I contemplated this modification.? To get that perfect non-binding installation the additional bearing would need to be supported on a shaft that is in alignment with the other two bearings as the 3rd is pressed into place.??
?
So when I looked at the distance between the bearings and the very short length the axle? is unsupported at the end of the body I figured it should make no difference.? My guess was it would not improve performance even if the 3rd bearing was installed perfectly.? But if not installed perfectly or the axle was not perfectly straight the slight misalignment could be the source of a slight, regular binding as the axle rotated.? So I passed on that modification.??
?
The possibility of screwing up the mount is very real, as my first-hand experience made painfully obvious... at least to me :)
 

¿ªÔÆÌåÓý

I added a third bearing simply by lubricating it slightly, inserting it part way, sliding the shaft into the center, and gently tapping the third bearing into place.

All went very smoothly this way and there was no chance of misalignment.

Laurel

On 4/25/25 9:43 AM, Paul Kanevsky via groups.io wrote:

? [EXTERNAL]

On Fri, Apr 25, 2025 at 10:09 AM, Chip Louie wrote:
Binding due to misalignment is one of the problems I found as a potential way to screw up my perfectly good G11 mount as I contemplated this modification.? To get that perfect non-binding installation the additional bearing would need to be supported on a shaft that is in alignment with the other two bearings as the 3rd is pressed into place.??
?
So when I looked at the distance between the bearings and the very short length the axle? is unsupported at the end of the body I figured it should make no difference.? My guess was it would not improve performance even if the 3rd bearing was installed perfectly.? But if not installed perfectly or the axle was not perfectly straight the slight misalignment could be the source of a slight, regular binding as the axle rotated.? So I passed on that modification.??
?
The possibility of screwing up the mount is very real, as my first-hand experience made painfully obvious... at least to me :)

1 - 6 of 6